Well, Ephesians 6:12 says clearly, “For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms.” We are further told in the Bible that this battle will continue until the Lord ends it once and for all.
Terrorists are tools of Satan, sent to wreak havoc and fear all around the world. While it looks as though we may not win this fight in the short term, we will in the long run! That is a promise from the Word of God.
Notice though, we are not called to win the fight; we are called to fight the fight! Ephesians chapter 6 goes on to explain how to do that. We must put on the armor of God so that we can stand firm in the face of evil. And we must pray!